1 18 iiir. i lesident's addbess. 



entirely without fossils, with the exception of a few boues or scales of 



TheFoBESTOF D in adjoins May Hill, and presents us with a new 

 mblage of strata ; for in the basin formed by the Old Red Sand- 

 stom trainable carboniferous and ferruginous deposits of the 



■itof Dean, supported by masses of Carboniferous Limestone, and 

 thinner bands of Shales and Sandstones, so that in descending order 

 we have the following strata : — Coal Formation, Millstone Grit, Moun- 

 tain Limestone, Lower Limestone Shales, and Old Red Sandstone. 



The I sous Limestone of the Forest of Dean is not more 



than L the thickness this formation attains in the Avon section. 



The Lower Limestone Shales, 16-5 feet thick, are very fossiliferous, 

 isting of alternations of Shales and Limestone, full of the ossicula 

 3, with a bone-bed near their base. The main Limestone con- 

 tains a succession of Brachiopoda, as Spirifera, Producta, and Orthis : 

 of Lamelltbranchiata, as Aviculo-pecten, Gardiomorpha; Gasteropoda, 

 Euomplialus and Belleroplwn ; Cephalopoda, as Goniatites, Orthoc 

 ActtTWceras, with the teeth and defensive spines of fishes. Some 

 he coral beds in the upper part of the series are rich in specimens of 

 (OZOA, belonging to reef-building groups of the ancient seas, 

 Michelinia, Amplexus, Lithostrotion, Syringopora, Lonsdaleia, and others, 

 and i us of the structure of the coral reefs of the present day. 



ical accumulations of peroxide of iron, 



intermingled with the calcareous deposits of the Forest of Dean, so 



that we should regard the iron as having constituted a portion of the 



ferruginous deposits have been long extensively worked 



and their mode of occurrence well understood. They have always the 



1 position, cropping round the basin-formed mass into 



whicl i Forest have been forced, and differing from 



re known elsewhere among the carboniferous rocks 



of England and South Wales, where the hematite is found in veins 



which cut the strata like mineral veins, whereas in the Dean Forest 



the iron deposits form a series of contemporaneous interbedded 



accumulations of the d carboniferous strata. 



Coal measures of the Dean Forest attain a thickness of 2,765 

 , and contain fifteen seams, of which eight are of a thickness of 

 2ft. and upwards. The thickest seam is about 5ft.: along the south- 

 I side of the coalfield the Millstone Grit and Carboniferous Lime- 

 stone are overlapped unconformably by the coal measures, according 

 to Mr. K. Gibbs. 



All the rocks we have surveyed from the western side of the Malverns, 

 Woolhope, May Hill, and the Forest of Dean are of the Pakeozoic ago, 



land ( torted either by eruptive agencies oi a series 



of p] - in post-ca >us and pre-triassio times, as is very 



well Bhown in this if the Malvern Hills, where the Keuper 



Sandstone is seen fco abut against the Syenite, and from this point 



>ur review of the Mesozoic Strata, which occupies the 



wide \alle\ of the Severn, and stretohee in a north-westerly direction 



